As a power source, an outboard motor mounted to an engine (internal combustion engine) typically has a shift unit that performs control of connection/disconnection of rotational power output from the engine and switches a rotation direction, an oil pump that feeds oil (lubricating oil) to the shift unit, and a water pump that feeds a coolant to the engine.
In Patent Literature 1, there is discussed an outboard motor provided with a drive shaft extending straightly downward from the engine and having first and second input shafts and a shift unit provided between the first and second input shafts. In addition, in the configuration discussed in Patent Literature 1, an oil pump for feeding oil to the shift unit is operated by receiving rotational power transmitted via an inner shaft directly connected to the second input shaft.
However, this configuration has the following problems. The second input shaft receives the rotational power transmitted from the first input shaft via the shift unit. For this reason, if the shift position is set to a neutral position, the rotational power is not transmitted to the second input shaft, and the oil pump is not operated. Therefore, when the shift position is set to the neutral position, it is difficult to feed the oil to the shift unit.
Furthermore, in the configuration discussed in Patent Literature 1, the water pump is provided over the shift unit. The water pump is provided on the drive shaft and is operated by receiving the rotational power transmitted from the drive shaft. In this configuration, during the operation of the engine, it is possible to operate the water pump regardless of the shift position of the shift unit.
A pilot shaft serving as a center of steering of the outboard motor is provided in front of the drive shaft of the outboard motor. For this reason, in the configuration of Patent Literature 1, in order to avoid interference between the water pump and the pilot shaft, it is necessary to increase a distance between the drive shaft and the pilot shaft or provide the pilot shaft over the water pump. However, if the distance between the drive shaft and the pilot shaft increases, a length from the pilot shaft to a center of the outboard motor also increases. For this reason, the moment of inertia in rotation of the pilot shaft of the outboard motor also increases, so that steering performance and gliding performance are degraded. In addition, if the pilot shaft is provided over the water pump, it is necessary to shorten the pilot shaft. For this reason, rigidity is degraded in a portion of the ship hull for supporting the outboard motor, and the steering performance is degraded.